US 2593525 A
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April 22, 1952 R. R. BECKHAM GLARE-REDUCING WINDSHIELD 2 SHEETS-SHEET 1 Filed Aug. 5, 1950 3 nvcnor @fed/Q @www April 22, 1952 R. R. BECKHAM @LAKE-REDUCING wINnsHIELD 2 SHEETSwSHET 2,
Filed Aug. 5, 1950 Cttornegi Patented Apr. 22, 1952 assises f GLARE-REDUCING w-IuDsHIELD Robert R. Beckham, Toledo, Ohio, assigner Ato Libbey-Owens-Ford Glass Company, Toledo,
Ohio, a corporation of Ohio Y Application August 5, 1950, Serial No. 17 75949 The present invention relates generally to the reduction of sun and sky glare, and more particularly to a novel curved and angled, laminated glass windshield, or the like, that is provided with a built-in glare screen having a fade-oli line, or aline ci uniform density, that is substantially parallel With the horizon when the windshield is mounted in its functional position in a vehicle.
This application is a continuation-impart of my copending application Serial No. 107,730, filed July 30, 1949: and the windshield with which this invention is primariiy concerned is a specially curved and angled structure, including a nonbrittle plastic interlayer, having a colored or neutral shaded glare-reducing area whichis preferably of a shade graduated from relatively deep at the top to practical extinction at the bottom, laminated together with one or more sheets of glass',
In producing the colored or neutralshaded, glare-reducing portions, or bands, in the plastic interlayer, it is desired that these portions have a cut-off or, better expressed, a fade-ofi line, between the colored or shaded area and the clear portion of the windshield, that is so formed that when the Windshield is mounted in its functional position in an automobile this fade-oli line will appear to be substantially straight and horizontal.
This is extremely important for the proper optical efect on the eyes of the driver or other occupant of the car, as they travel from side to side of the windshield; for appearance of the automobile; and to insure conformance to motor vehicle codes which require a specified amount ci visibility throughout the critical viewing area of the windshield. Y
Now the provision of a horizontal fade-oli` line between the shaded and unshaded areas of a plastic interlayer that is to be mounted between the glass sheets of a iiat windshield, presents little or no diiculty.
For example, for this purpose the plastic needs simply to be colored in a manner to give a straight fade-oli line in the flat.
However, this relatively simple and Straightforward method cannot be employed to give a properly oriented fade-off line for the shaded area of bent and angled windshields, and particularly for one-piece bent windshields which have'their principal bent curvature in the horizon-tal plane (that is, along their longitudinal axes), which have an outline that is curved at the top and 'bottom, and which are mounted inthe automobile at an angle to the vertical.
Such horizontally bent, and vertically angled windshields present an entirely ydii'erent and unique problem.
rlhus, surprisingly enough, it is impossible to provide a straight, horizontal fade-off line in a horizontally bent andV vertically angledV wind- 2Y shield if the shaded portion of the plastic interlaye'iI was straight in the flat.
Inf-act, I `have discovered that the only way to arrive at' a substantially straight and horizontal fade-ofi linefor the glare-reducing area .of the interlayer of a horizontally bent, laminated windlou shield which, when mounted in its functional position in the automobile, is at an angle to the vertical',.is byutilizing a shaded interlayer having a fade-off line that is curved in the fiat to an eX- tent, and in a direction, sufficient to compensate ifoithe Veiiect of the horizontal bend and the vertical angularity of the windshield on the apparent path or direction of thefade-off line.
It is therefore a primary aim of this invention to provide a glare-screening interlayer, for windshields of the above general shape andvangularity, which has a colored or shaded area whose fade-off line'is of such curvature in the at that it will appear to the observer to follow a substantially straight and horizontal path when the bent windshield is mounted in its functional position in an automobile. 'Y i This may be accomplished in a number of specifically different ways depending on whether the glare-reducing portion of the interlayer is to be dyed, printed or otherwise applied tothe plastie, the' important vpoint being that, when the colored or shaded interlayer is incorporated into a windshield by' laminating with two sheets of glasstliat arebent in a horizontal plane, and the composite structure then mounted at an angle to the vertical in an automobile, the bottom or cutoff line of thecolored area ofthe plastic will appear as a straight, horizontal line to the driver and eupants of the car. l
Arither' bj'ectv is the provision, in an antoniov bil, f'a horizontally bent and vertically angled windshield having a built-in glare screen with a cut-oli line that is substantially parallel to the horizon. I l ,A ,A
Further objects and advantages of the invention vwill-becoirie more apparent during the course of the following? cifascription,y when taken in conilectio'r'iI withtlie accompanying drawings.
yIn the drawings, wherein like 'numerals' are einplyed toV designate like parts throughout the sal g1 `1 is ariciev'auon' or the winpdshiidipf' the iiveiition's viewed from the interior of an automobile' 'which it is installed; y
FigiA 2v'is` a vertical sectional view through the windshield arranged in the angled position which it occupies inthe' automobile; Y
Fig. 3 is a perspective plan view of two sheets of .glass and a colored or shaded plastic vinterlayer prior to assembly into a sandwichV and laminatinginto a nished Windshield;
. Eig( 45 is aV perspective view of a laminated safety glass windshield, having its principal bent curvature in the horizontal plane, or along its longitudinal axis, and provided with a glarereducing portion in its plastic interlayer;
Fig. 5 is a vertical section through the windshield of Fig. 4, taken substantially along the line 5-5 and showing the angle at which the windshield will be mounted when in its functional position in the automobile;
Fig. 6 is an elevation of a sheet of plastic which has been colored to produce a glare-reducing portion therein, and showing an interlayer for a bent laminated windshield cut from the plastic sheet and having a straight cut-oir' line in the iiat;
Fig. 'I is a front view of a horizontally bent, laminated windshield, into which the interlayer of Fig. 6 has been incorporated, showing the appearance of the fade-off line when the Windshield is mounted in its functional position in an automobile;
Fig. 8 is a vieW similar to Fig. 6 but showing a sheet of colored plastic after it has been distorted according to this invention, and showing how an interlayer is cut therefrom to give a curved cut-off line in the flat; and
Fig. 9 is a view similar to Fig. 7 but showing how the interlayer of Fig. 8 Will look when incorporated into a horizontally bent, laminated windshield and the windshield mounted in its functional position in an automobile.
` Referring now more particularly to the drawings, there is illustrated in Fig. 1 a windshield III, produced in accordance with this invention, as it appears from the front seat of an automobile II in which the windshield is mounted. As eX- plained above, this windshield is of conventional laminated construction in that it comprises two sheets of glass I2 and I3 and a non-brittle plastic interlayer I4 (Figs. 2 and 5). However, it departs from the ordinary construction by being specially shaped, and by having its plastic interlayer I4 provided with a glare-reducing area or band I5 which is colored or of a. neutral shade and graduated in intensity from relatively dark at the top to practical extinction at the bottom, ending in an almost impercepticle cut-off line I6 between the colored or shaded and uncolored or unshaded areas.
The purpose of this is to provide. withinthe windshield, a glare-reducing area in which the color or neutral shade is relatively deep or intense at the top of the windshield, which is the area presenting the greatest glare, and tapers oil gradually to a very low intensity. or to no shade or color at all, as it approaches the essential sighting area I'I of the windshield.V
It will be noted from Fig. 1 that to the eye of an observer in the car the cut-off line I6 of the colored or neutral shaded area I5 appears as a straight, lhorizontal line. However, this is not actually the case, and I have discovered that in the specially curved, shaped and angled windshields now coming into common use in the modern streamlined and revolutionary designs of automobiles proposed for, and currently on, the market, a cut-off line in the colored area of the plastic interlayer that is actually straight and horizontally arranged will not appear to be so when laminated with the glass sheets and mounted in the automobile.
To illustrate, the windshield shown in Fig. 4 is of characteristically modern lshape in that it has its principal curvature in the horizontal plane. Now this particular windshield is intended to be mounted in its functional position in an automobile at an angle to the vertical as shown in Fig. 5; and in this position, the cut-ofi' line I6 of the glare-reducing portion I5 should appear as a substantially straight, horizontal line.
However, as illustrated in Figs. 6 and 7, when an interlayer for such a windshield is produced in the prior known manner by rst forming a straight band of colored or neutral shade across one margin of a plastic sheet (Fig. 6), and then cutting an interlayer I4 to the Windshield outline and with a glare reducing portion I5 having a straight cut-off line I6 from the shaded plastic, it will be found that when this interlayer is sandwiched between two pieces of bent glass and mounted in the automobile that the cut-off line will'no longer appear to be either straight or horizontal.
"Instead, it will appear in the horizontally bent and vertically angled windshield as shown in Fig. 7, that is, as a curved line which runs down rather sharply at the two opposite ends. This is of course an unsatisfactory condition, not only because of its undesirable appearance, but because the end curves run into the essential or critical viewing area I1 of the windshield.
Consequently, an interlayer having a shaded portion which actually has a straight cut-off or fade-out line cannot be used to obtain the desired result in windshields of this form. Instead, I have found that it is necessary to produce a glare-reducing area with a cut-off line which, regardless of its form when the plastic sheet is in the fiat, is so designed that it will appear as a substantially straight, horizontal line when the shaded plastic has been laminated into the bent windshield and the windshield mounted at an angle in the automobile.
Thus, in the windshield I0 of Figs. 1 to 3, and which is characteristic in shape, contour and angled position to the newer modern designs, it will be seen that, in order to obtain the straight horizontal effect of cut-ofi line seen in Fig. 1, it has been necessary to provide a colored area I5 having a cut-oil line that is actually not straight at all, and so cannot be horizontally arranged. Instead, as best seen in Fig. 3, the cut-off line I6 is actually curved and is somewhat similar in contour to the curvature of the top lines of the glass sheets I2 and I3.
Now the coloring of a plastic sheet in a manner to produce a glare-reducing portion of this shape that is properly graduated in color or shade from top to bottom, and which has an ahnost imperceptible cut-off line, presents a considerable problem.
Nevertheless, it can be done in a number of ways and I have discovered one novel and yet relatively simple way of accomplishing it, which has been set forth in detail in my cci-pending application Serial No. 107,730, which has already been referred to, and of which this application is a continuation-in-part.
However, regardless of how the plastic sheet I8 is colored, it is customarily trimmed as shown in Fig. 8 to form an interlayer I4 of the lwindshield outline and to remove the marginal por tions or Selvage of the sheet, The interlayer I4 is `then assembled together with two pieces of glass as shown in Fig. 5 to form a glass-plastic sandwich which is then laminated under heat and pressure to form a composite, unitary structure. When this laminated glass structure is mounted as a windshield in an automobile at the angle shown in Fig. 5, it will exhibita colored glare-reducing area I5 having a horizontal cutoff line I6, as shownin Fig. 9.
It will be appreciated that the glare-reducing portion of the windshield of this invention can be produced by printing, or in other suitable ways, as well as by dyeing; that the invention is also applicable to plastic interlayers in which the glare-reducing portions are shaded bands of unvarying density; and to plastic interlayers which are shaded or colored over their entire areas,
with the shade Varying from full density at one edge to very light density at another.
In the latter case there would, of course, be no cut-off or fade-off line other than the edge of the interlayer, but the advantage of the invention in that case would be to give imperceptible, horizontal lines of uniform density across the shaded area, so that, as the eye of an observer travels from side to side of the windshield along any horizontal path it will be looking through the same density of shading at all points.
In fact, it is to be understood that vthe forms of the invention herewith shown and described are to be taken as illustrative embodiments only of the same. and that various changes in the shape,
layer of plastic material bonded to one another to provide a unitary structure, said windshield being bent along the longitudinal axis thereof with its opposite end portions curving rearwardly toward said body and being positioned at an angle to the vertical with the upper edge disposed inwardly of the lower edge thereof when mounted in said functional position, and a shaded area on said plastic interlayer comprising a colored band extending from one side to the other of the windshield along the upper marginal edge portion thereof and decreasing in intensity from the top of the interlayer toward the bottom thereof to an imperceptible substantially horizontal fadeoff line along the bottom of said shaded area and with said colored band exhibiting uniform density from one side to the other along any horizontal line between the fade-01T line and the upper edgeofthe windshield when the windshield is in said functional position and viewed from the interior of the automobile.
' ROBERT R. BECKHAM.
I REFERENCES CITED The following references are of record in the le of this patent:
UNITED STATES PATENTS Number Name Date 2,315,103 Anderson Mar. 30, 1943 FOREIGN PATENTS Number Country Date 370,656 Great Britain Apr. 14, 1932